If you are experiencing foot or ankle pain and your podiatrist cannot determine the cause through a physical examination, you may need a computerized axial tomography scan or CAT scan. (This test is also called a computer tomography or CT scan.)

Need for CAT scans

Some conditions that a CAT scan may diagnose include:

Arch deformities.

Arthritis, both degenerative and rheumatoid.

Bone tumors.

Cysts.

Flat feet.

Other foot and bone deformities.

Foreign bodies.

Fractures, including stress fractures.

Infection.

Osteonecrosis (bone death).

Overview of CAT scans

A CAT scan uses x-ray technology, but is often considered more advanced than a conventional x-ray since it can create a three-dimensional picture that allows your doctor to more accurately assess the problem.

During a CAT scan, your foot will pass through a doughnut-shaped x-ray machine. This machine will rotate and take internal pictures of your foot and/or ankle. Using computer technology, the machine combines numerous x-ray images to generate cross-sectional views and three-dimensional images of the inside of your foot and ankle.

The detail of these images will give your doctor a clear picture of your foot. This clarity will help your doctor better diagnose your problem. For example, an image from a CAT scan will show a difference between a simple cyst and a solid tumor.

CAT Scan Restrictions

The amount of radiation that you are exposed to during a CAT scan is minimal, so typically there are no restrictions for having this exam. However, if you are pregnant, especially in your first trimester, it is not recommended that you undergo a CAT scan due to potential adverse effects on the fetus.